Postoperative Pain

The trial prioritises movement-evoked pain over resting pain because coughing, deep breathing, and mobilisation are directly linked to respiratory function and early recovery. Pain is measured with an 11-point NRS where 0 indicates no pain, 1–3 mild pain, 4–6 moderate pain, and 7–10 severe pain. A patient-controlled analgesia solution containing butorphanol, oxycodone, and tropisetron is provided to all participants for the first 48 hours postoperatively. Postoperative pain is a common surgical complication involving physiological and psychological responses to trauma. About 10% of acute postoperative pain cases become chronic postoperative pain. The risk of chronic postoperative pain is affected by patient factors, disease, surgery type, and pain management protocols. Persistent postoperative pain can delay rehabilitation through anxiety and systemic pathological changes. The primary outcome of the trial is the incidence of moderate-to-severe movement-evoked pain at 24 hours, defined as NRS 4 or higher after three consecutive forced coughs or deep breaths. An NRS score of 4 or higher triggers rescue intravenous oxycodone hydrochloride administration either proactively or on patie…